fix(fixRequestBody): support content-encoding on request body

[robbtraister]

Description

The body-parser package supports the content-encoding header on the request (See here). When reconstructing the body for proxied requests that have already been parsed, we should respect the content-encoding header and preserve the original compression algorithm.

Motivation and Context

Without this patch, an encoded request will fail when the upstream server attempts to read it due to a mismatch between the compression algorithm reported and the actual payload received. An alternative approach would be to remove the content-encoding header from the proxied request, but this seems more appropriate.

How has this been tested?

I added a unit test to verify that the reconstructed body is encoded as expected.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[pkg-pr-new]

npm i https://pkg.pr.new/http-proxy-middleware@1142

commit: 80f182f

[chimurai]

Thanks!

[coveralls]

coverage: 95.408% (-0.9%) from 96.335%
when pulling 78df26d on robbtraister:fix-request-body/content-encoding
into b67d34d on chimurai:master.